The invention relates generally to photonic crystals, and relates more particularly to the tuning, modulation and switching of optical signals in integrated photonic crystal devices. Specifically, the present invention relates to a method and apparatus for thermo-optic modulation of optical signals using photonic crystal structures.
Active manipulation of light transmission in a planar lightwave circuit can be performed by changing the temperature of a region of a planar waveguide. A temperature change results in a change the optical parameters of the planar waveguide (e.g., a change of the effective refractive index seen by the signal confined within the photonic crystal lattice, waveguide or cavity). Correspondingly, optical parameters such as the resonant frequency, gain coefficient and lasing threshold can all be easily tuned by changing local temperatures in the corresponding circuit.
Conventional thermo-optic switches such as Mach-Zehnder switches, while effective, tend to be relatively large and slow devices that consume a great deal of power. For example, typical Mach-Zehnder switches have a footprint of several centimeters, a modulation speed of a few KHz, and consume approximately 100 mW of power. It is therefore desirable to achieve more efficient thermo-optic control of optical signals.
Thus, there is a need for a method and apparatus for thermo-optic modulation of optical signals using photonic crystal structures.